Sealing means for an annular passage formed between two coaxial portions of a pair of units movable with respect to one another



Jan. 12, 1965 SOGUEL 3,164,954

SEALING MEANS FOR AN ANNULAR PASSAGE FORMED BETWEEN TWO COAXIAL PORT 5 OF A PAIR OF UNITS MOVABLE WITH R ECT TO ONE ANOTHER Filed April 15. 1960 2 Sheets-Sheet 1 Jan. 12, 1965 so u 3,164,954

SEALING MEANS FOR AN ANNULAR PASSAGE FORMED BETWEEN TWO COAXIAL. PORTIONS OF A PAIR OF UNITS MOVABLE WITH RESPECT TO ONE ANOTHER Filed April 13, 1960 2 Sheets-Sheet 2 United States Patent Office 3,164,954 Patented Jan. 12, 1965 SEALING MEANS FOR AN ANNULAR PASSAGE FORMED BETWEEN TWO COAXIAL PORTIONS OF A PAIR OF UNITS MOVABLE WITH RESPECT TO ONE ANOTHER Rene Soguel, Les Hauts-Geneveys, Neuchatel, Switzerland Filed Apr. 13, 1960, Ser. No. 21,948 Claims priority, application Switzerland, Oct. 25, 1955, 28,805/55 5 Claims. (Cl. 5890) This invention relates to sealing means for an annular passage formed between two coaxial portions of a pair of units movable with respect to one another, and in particular to means for forming a tight seal in the annular passage usually existing in watches where the winding and hand setting stem passes through an opening of the watch case.

The present application is a continuation-in-part of my patent application Serial No. 617,823, filed October 23, 1956, and now abandoned.

In this particular case the movable unit comprises the winding and hand setting stem and the crown fixed thereto to actuate said stern, and the fixed unit is formed on or carried by the watch case. In most instances a tube is fixed to the watch case and the crown is recessed so as to be provided with an outer annular portion surrounding said tube. The annular passage to seal for ensuring a watertight closure of the watch case is thus formed between said fixed tube and said outer crown portion. Instead of being formed between an inner portion of the fixed unit and a outer portion of the movable unit, the annular passage in question could also be formed between an inner movable portion either of the stem or of a tubular projection of the crown and an outer fixed portion either of a tube carried by the watch case or of the watch case itself.

To provide a tight seal in an annular passage of the type indicated one of the simplest solutions consists of locating a rubbery sleeve in said passage, said sleeve being fixed to one of said units. To ensure the tightness desired said sleeve accordingly must have a portion in sliding con tact with the. other unit.

In the cases known in the ant wherein an annular passage is tightly closed by a rubbery sleeve, this sleeve is mounted so that a cylindrical surface portion thereof slides along a corresponding surface portion of one of said units when the latter are moved with respect to one another. Now, while these known sealing means produce satisfactory results as long as one of said units is moved in axial direction with respect to the other unit, several drawbacks wereappearing when said units are rotated with respect to one another, in particular with sleeves as small as those used in watches for producing a tight seal of the winding stem passage across the watch case.

To ensure a tight contact between a cylindrical inner surface of a rubbery sleeve and a corresponding outer surface of an inner portion, the sleeve must be compressed to such an extent that it produces a great friction between said units; As a consequence thereof the movable unit can only hardly be rotated with respect to the other unit and said sleeve also causes a substantial wear of said inner portion outer surface.

With a rubbery sleeve fixed to a crown in a recess thereof, the rotary motions of the crown thus produce a Wear of the tube. Consequently, if the crown does no longer ensure the tightness of the watch case after the watch has been carried, one ought to replace not only the crown, but also the watch case tube. However, if watchmakers generally have spare crowns in stock, they do not always possess tubes and even if they do, they can hardly fix a tube to the watch case so that it forms a watertight joint therewith.

It is therefore an object of the invention to locate said rubbery sleeve in an annular cavity formed in said outer portion and delimited by two plane faces perpendicular to the axis of rotation of said one unit with respect to the other one and to provide means to fix for rotary motions said sleeve on to said inner portion, whereby the end faces of said sleeve slide on said plane faces of said outer unit, when one of said units is rotated with respect to the other one.

With sealing means of this type, the rotations of the movable unit do obviously no longer cause any wear neither of the outer face of said inner portion nor of the inner face of said sleeve in contact with said inner portion. With a crown carrying a rubbery sleeve which does not rotate around the watch case tube, for instance, the water tightness of the watch case is ensured for a period substantially longer than with a crown provided with a rubbery sleeve rotating around the watch case tube when the crown is driven in rotation.

In my Swiss Patent No. 302,613 I have already disclosed a crown provided with a packing which does not rotate around the watch case tube but remains stationary therewith. This packing is however composed of a tubbery sleeve and a metal ring interposed between said sleeve and the bottom of the crown recess. With respect to a sleeve in contact with the bottom of the crown recess, the metal ring of the crown disclosed in said patent obviously slides easier on the recess bottom.

The sealing means disclosed in said patent are, however, expensive because said metal ring as well as the bottom of the crown recess must be machined with a great precision. Moreover, these sealing means have the drawback that they necessitate a great total height of the crown.

It is therefore also an object of the invention to provide means for fixing the rubbery sleeve to said inner portion while avoiding any increase of the total height of the crown.

Still further objects of the invention will become apparent in the course of the following description.

Several embodiments of the sealing means according to the invention are represented by way of example in the drawings annexed to this specification, wherein similar reference numerals designate like parts throughout the same.

In the drawings:

FIG. 1 is a sectional view of a watch crown set in of said sealing means also provided in a watch crown;

tightly fixed to the watch case 3.

FIG. 3 is a plan view of one element of this second embodiment;

FIG. 4 shows a third embodiment in axial section of said sealing means which are also located in a watch crown;

FIG. 5 is a sectional view of one element of this third embodiment; 7

FIG. 6 is a sectional view similar to those of FIGS. 1, 2 and 4 showing a fourth embodiment of said sealing means; V 7 FIG. 7 is a perspective view of an element common to FIGS. 2, 4 and6.

FIG. 8 is a perspective view of a modification of the element shown at FIG. 7, and

FIG. 9 is a sectional view of a part of watch in which the tightness of the stem passage across the watch case wall is ensured by sealing means similar to those of FIGS. 4 and 5.

' The sealing means shown in FIG. 1 are provided in a watch winding and hand setting crown comprising a body member 7b fixed to a winding and hand setting stem 1 by means of a tapped central tubular projection 8. An annular recess 9:: is' formed in the crown body member 75. This recess 9a has the form of a cylindrical crown and its bottom 12b extends perpendicularlyto the axis of rotation of the crown. A rubbery sleeve 16 is located in the recess 9a in which it is axially held in place by a ring 13 fixed to the crown body member 7b by press fitting or by setting.

The rubbery sleeve this surrounded by a metal sleeve 11a and it encompasses the Watch case tube 2 which is 'The sealing means comprising here sleeve 10 tightly close the annular passage formed between the fixed unit comprising tube 2 and the movable unit comprising crown 7b at three places: along the two plane end faces of sleeve 14) which are in contact with the bottom 12b of recess 9:: and with the ring 13, respectively, and along the cylindrical inner wall of said sleeve which is in con-' tact with the outer cylindrical surface 4 of tube 2. Moreover, the metal sleeve 11a presses the rubbery sleeve 19 on surface 4 of tube 2 so as to produce a greater friction of sleeve 10 around tube 2 than along the end faces of this sleeve 1% which are in'contact with the bottom 12b of recess 9a and with ring 13. Sleeve 10 will accordingly remain stationary with tube 2 whatever are the rotary movements of the movable unit comprising the crown.

When the crown is moved axially from its winding to its setting position, or vice versa, or when the crown is set in place on tube 2, the sleeve 10 can however slide without any difficulty along said tube, without leaving neither ring 13 nor the bottom 12b of recess 9a.

To avoid too great a reduction of the sizes of the end plane faces of sleeve 10, the material of this sleeve is preferably treated 50 that' its friction coefiicient is smaller along said end faces than along the cylindrical inner face in contact with face 4 of tube 2. i

The sleeve 10 may consist of a material comprising, for

' instance, 70% by weight of polyvinyl chloride and 36% of dibutyl phthalate. Rectangular thin sheets of this material are then put into a waffie-iron-like mould sprinkled with talc and heated at a'ternperature comprisedbetween 210 and 230 F. At that temperature the said plastic material softens enough to absorb talc in its surfaces. -Thethickness of the impregnated'portion of the plastic material does, however, not exceed 2 to 3 thousandths of an inch.

Rings having the form of sleeve 15) canthen be stamped out of the sheets prepared as'described above.

As a result of this manufacturing method the sleeves it) have only their end plan faces impregnated with talc, whereas the cylindrical'faces thereof are free from talc. The frictioncoefficient of sleeve lti along its cylindrical inner" face in contact with face 4 of tube 2 is thus greater 4 than the friction coefficient along the plan end faces of sleeve 19. The total surface of said end faces may thus be even greater than the surface of said cylindrical inner face of the sleeve 14), without changing anything to the function thereof described above. a

It will be observed that this tale impregnation, which is a known method of reducing the friction, does not re duce the tightness of the seal ensured by sleeve it although said impregnation stifiens the outer faces of the sleeve so treated.

instead of the treatment described, the plane end faces of'the sleeve 1% could also be subjected to any other treatment to render them more slippery, for instance by forming a thin coat of another product as talc on them.

In the second embodiment (FIGS. 2 and 3), the sealing means shown also form a tight closure of the annular space existing between a watch winding and hand setting crown and a watch case tube 2. FIG. 2 shows that tube 2 is tightly set with force fit into an opening of the watch case 3, so as to form a passage across the watch case for the winding and hand setting stem 1 of the watch movement. The outer surface 4 of the tube portion protruding from the watch case is cylindrical. This surface dis however not polished. On the contrary, it is provided with a set of infinitestimal grooves S forminginfinitesimal ribs 6 therebetween. To obtain that structure of surface 4 the tubes 2 are passed between drums having cylindrical faces milled in different directions. The grooves obtained thereby cannot be seen with the naked eye, their depths being substantially the same as that which can be observed on work pieces drawn from a diamond die. A crown 7 formed with a tapped central tubular projection 8 is screwed on to the end of a stem 1 as in FIG. 1. An annular recess 9 is also provided in said crown to receive a portion of tube 2. Y

The tightness of the annular passage formed between the inner portion of the fixed unit constituted by tube 2 and the outer portion of the movable unit constituted by the outer wall portion of crown 7 is ensured by sealing means comprising a rubbery sleeve 10 compressed radially against the surface 4 of tube 2 by a metal sleeve 11 and axially against the plane face 12 forming part of the bottom of recess 9 by means of a ring 13 fixed to the crown at the opening of said recess. Once the ring 13 is fixed to the body member 7 of the crown, the recess constitutes an annular cavity provided in the outer movable portion adjacent said annuiar passage formed between crown 7 and tube 2. Said cavity is facing said inner portion constituted by tube 2. Although not quite necessary in this embodiment, both end faces of sleeve 1% can also be impregnated with talc in order to reduce the friction between this sleeve and the body member of the crown so as to prevent the former from driving the latter around the tube 2 when the crown is driven itself in rotation. Moreover, the metal sleeve 11 has also ap proximately the same height as the rubbery sleeve 10, b instead of pressing sleevelt over almost its whole heighf', the inner surface of sleeve 11 is bevelled at 14 and 15 so as to leave only a small cylindrical surface portion 16 in the center of this sleeve. The sleeve 19 is accordingly compressed around tube 2 only by this surface 16 of sleeve 11, whereas'the truncated conical faces 14 and 15 thereofare forming together with the surface 4 of tube 2 expanding spaces for thematerial of sleeve it so as to enable a free deformation of said rubbery sleeve. The lattercan thus compensate the manufacturing irregularities of the crown to an extent which is much more.

importantthan with the crown of the first embodiment. The sleeve 1%) will remain in tight contact with the bottom face 12 of the crown body recess 9 and with the inner face of ring 13 even if the distance between these two faces is' varying within a reiatively large range. in addition thereto the truncated conical. inner faces 14 and 15 of sleeve 11 have still the advantage to permit thesleeve 19 ofcompensating an angular difference betweenthe crown and the tube axis. Because of the resiliency of the end portions of sleeve 10, the crown can obviously tilt more easily than in the first embodiment thus facilitating the rotations of the crown everywhere it is not coaxial to the tube 2, for instance, because of the manufacturing differences which can cause a wrong location of the watch movement in its case or of the stem in the movement, or because of the manufacturing diiferences in threading the stem or the central protruding sleeve portion of the crown, or, finally, in setting the tube into its opening of the watch case.

Experiments made with a metal sleeve bevelled in the manner disclosed above have shown that such a sleeve compresses the rubbery sleeve enough around tube 2 to produce between said rubbery sleeve and said tube a friction greater than between said rubbery sleeve and, on the one hand, the face 12 of crown 7, and on the other hand, the ring 13. The small grooves 5 and the corresponding ribs 6 of tube 2 in crease of course the friction between sleeve and tube 2 when the crown 7 is driven in rotation. There is, however, no absolutely strong need of providing tube 2 with said grooves and said ribs. The crown shown in FIG. 2 could also be set on a tube polished as usual. The sealing sleeve 10 would then also slide within the crown along its end faces and not around the tube 2 along its inner cylindrical face when the crown was driven in rotation.

Instead of a usually polished tube or instead of the tube with the grooves and ribs described, a prismatic tube 2a as shown in FIG. 8 could also be used. In this figure the part 4a of tube 2a protruding from the watch case is provided with eight fiat faces 17 separated from one another by rounded edges 18.

Experiments made with such tubes have shown that the plastics available nowadays are resilient enough to make sleeves as shown at 10 which come in tight contact with a prismatic tube as shown in FIG. 8 under the action of a bevelled metal sleeve as that of FIG. 2.

The sleeve 11 could be plain. It is however preferably made as opened ring so as to have some resiliency and to exert a more regular pressure on the sleeves 10 of a series. If the sleeves 11 and the tubes 2 of a series can be manufactured with reasonably small differences in their sizes, it is indeed not possible to manufacture a series of rubber sleeves with the same precision. It thus occurs that some of said rubbery sleeves are compressed so strongly on said tubes that the crowns can hardly be moved thereon in axial direction from the winding to the setting position and vice versa, while other gaskets of said series are compressed too little on said tube in order to ensure a tight seal of the'passage for-med between the tube and the crown. A metal sleeve 11 provided with an axial slot extending in a plane passing through the crown axis is however not advantageous since the materialof the rubbery sleeve is often so soft that it would'enter the slot of the metal sleeve and prevent the latter from working in the intended yieldable manner. FIG. 2 shows that the metal sleeve 11'is provided with a slot 19 parallel to the-sleeve axisbut extending substantially in a tangential plane of said sleeve.

Experiments made with opened sleeves as described above have shown that the material of the rubbery sleeve does not enter the slot of said metal sleeve, so that the latter can work resiliently without any difiiculty.

The sealing means according to the third embodiment (FIGS. 4 and 5) are also mounted in a device comprising a tube 2 having a cylindrical portion protruding from a watch case 3, said protruding portion also having an outer surface 4 provided with a net of fine grooves and ribs as in the second embodiment. The crown7a of this third embodiment is also made with a central tapped tubular projection '8 by means of which it is screwed on to a stem 1 and an annular recess 9a is provided in this crown to receive a portion of tube 2' as well as a gasket 20 having the forrn of a cylindrical sleeve and a metal constitute an intermediate solution between the two ring 21 pressing the central portion of said gasket on to tube 2 to prevent this gasket from rotating when the crown is driven in rotation. As in the second embodiment the gasket 20 and the ring 21 are axially held in place in recess 9a by means of a ring 13a fixed to the crown body member at the opening of said recess.

The gasket 20 could also be stamped out of a sheet rubber having its faces impregnated with talc as in the second embodiment. The end faces of the gaskets obtained in this manner would be plan. Better results are however obtained by moulding the gasket in the form represented at FIG. 5. This figure shows that the end faces 22 and 23 of gasket 20 are slightly bulged. The outer face of this gasket is provided with a peripheral groove 24 extending all round the latter. Groove 24 is semi-circular in cross-section and it serves as lodging for ring 21 which has a circular cross-section.

Gnce the gasket 20 has been set in place into the crown as shown in FIG. 4, its faces 22 and 23 become fiat under the pressure exerted by the gasket on the bottom face 12a of recess 9a and on the retaining ring 13a. The friction etween these end faces of the gasket and the corresponding faces of the movable unit of the winding device is smaller than with gaskets having fiat end faces. This friction could even be reduced by impregnating the said end faces with talc as in the first embodiment. However, instead of placing rectangular pieces of plastic into hot moulds powdered with talc and stamping afterwards gaskets out of said pieces, said gaskets should first be stamped and then placed into said moulds so that their end faces come in contact with the two mould faces. To avoid any talc impregnation of the inner cylindrical face of said gaskets, small wooden plugs could, for instance, be placed into said gaskets before introducing them into said moulds.

As in the second embodiment the metal ring 21 could also be split in a tangential direction to compensate the manufacturing differences of said rings, said tubes and the tightening gaskets in order to obtain the same compression of gasket 20 on to tube 2 in all the winding devices of a series. Instead of a polished tube or tube 2 of FIG. 7 the prismatic tube shown at FIG. 8 could also be used.

The free portions of gasket 20 of this third embodiment extending above and below ring 21 compensate, as in the second embodiment, on the one hand, the height differences occurring in the crowns of a series between the retaining ring 13:: and the bottom face 12a and, on the other hand, the angular differences occurring between stem 1, crown 7a and tube 2. To prevent the free portions of gasket'2t from wrinkling around ring 21, for instance, when the crown is moved in an axial direction with respect to the tube, the relative sizes of gasket 2i) and of ring 21 should preferably be chosen so that the free spaces between ring 21, and, on the one hand, the bottom space of the crown cavity, and, on the other hand, the retaining ring 13a are smaller than the thickness of gasket 20. When choosing the sizes of said gasket and of the metal ring in this manner, the gasket can leave neither face 12:: nor ring 13a because it cannot enter said free spaces.

The sealing means according to the fourth embodiment preceding embodiments. In this fourth embodiment the tightening gasket 2-0 of the crown is compressed on to tube 2 by a metal ring 21a as with the third embodiment. This ring 21a is however trapezoidal in cross-section in order to compress the gasket 20 on to tube 2 only by means of its inner cylindrical face 25, while its two truncated conical faces 26 and 27 leave the end portions of gasket 20 free as faces 14 and 15 of sleeve 11 in the second embodiment. In this fourth embodiment the tightening gasket could be made as described above with reference to'FIG. 5. Moreover this gasket would be provided with a peripheral groove having the same shape in cross-section as that represented at FIG. 5. Once the trapezoidal ring 21a has been set in place around gasket 20, the lat ter will be deformed so as to come contact with faces 25, 26 and 27 of ring 21a.

To prevent the gasket 2t) of this fourth embodiment from leaving either the bottom face 12:: of cavity 9a or the retaining ring 13a and from turning up around ring 21a, the sizes of gasket 29 and of ring 21a are chosen with respect to the depth of cavity 9:: as in the third embodiment, i.e. so that the free spaces between the truncated conical faces 26 and 27 of ring 21a and, on the one hand, the bottom of cavity 9a, and, on the other hand, the retaining ring 13a are narrowerthan the thickness of gasket 20.

Instead of a polished tube or the tube of FIG. 7, that of FIG. 8 could obviously also be used this fourth embodiment.

In the three last embodiments described it is thus only the central portion of the tightening gasket which is compressed on to tube 2. When this tube has the form represented at FIG. 7, the crown can be moved axially with respect thereto as easily as with a polished tube. Moreover, the ribs 6 of said tube are too small to wear the gasket when the crown is moved axially with respect to the tube. Although the gaskets described are substantially less moved with respect to the tube'than the usual gaskets which are rotating around the watch case tube when the crown is itself driven in rotation, it could be observed tiat the material of the gasket can be chosen so that the gasket does not adhere to the metal of the tube,

even if it remains a relatively long period at rest on said tube. Such an adherence was observed with the first materials used for the tightening gaskets and it was due to the chemical processes occurring between the plastic and the metal. a

To prevent water from entering the space comprised between the outer wall of the crown cavity and the tightening gasket, the retaining ring 13, 13a is advantageously fixed to the crown as tightly as possible.

In the three last embodiments the sealing means are located in a cavity of the movable unit and the metal ring 1 surrounding the rubbery sleeve presses the central portion of the latter on an inner portion of the fixed unit. FIG; 9 shows the sealing means of FIGS. 4 and used in a somewhat different manner. The cavity receiving the sealing means is provided as shown at 23 in the wall of the watch'case 3a. Instead of the gasket 29 of FIGS. 4 and 5, that of another embodiment could of course also be used just as well. The gasket 20 shown in FIG. 9 is surrounded by a metal ring 21 which could also be split in a tangential direction and which presses the central portion of gasket 20 directly on to the winding and hand setting stem 1 of the watch movement.

This gasket 2% is retained axially in place in the watch case cavity 28 by a ring 29 fixed in a lodging of the watch case So provided at the opening of cavity 28.

The application shown in this FIG. 9 has many advantages. While the machining operations to provide the cavity 28 in the watch case 3a are the .same as those to provide a recess in the crown body member, while the gasket 29, the metal ring 21 .and the retaining ring 2h are the same as in the cases described above and while the assembling operations of the latter elements in the fixed to stenrl to actuate the latter, i.e. the same crown as used with watch cases which are not watertight. The

a crown 39 can accordingly be made as small as desired as well as regards its heightas its diameter so that it does not perturb the aesthetical effect of the watch as the usual big watertight crowns. In other words, the sealing 8 means according to the invention have also the advantage that they can be mounted in the watch case itself thus enabling the production of a fine watertight watch without any risk of perturbing the appearance of this watch with a crown out of proportion with the case.

\Vhile several embodiments of the invention have been described in detail, it will appear obvious to those skilled in the art that various changes in the sizes, shape and arrangement of parts could be resorted to without departing from or sacrificing the spirit of the invention defined in the subjoined claims.

I claim: I 1. In combination; an inner portion of a first unit and an outer portion of a second unit, said inner portion having an axis and said outer portion surrounding said inner portion and extending coaxially thereto, one of said units being arranged for rotary motions about said axis with respect to the other unit, said outer portion having an annular cavity facing said inner portion, said annular cavity being delimited in axial direction by two plane faces substantially perpendicular to said axis; a rubbery sleeve located in said cavity between said two plane faces and surrounding said inner portion, said sleeve having an inner surface contacting the outer surface of said inner portion, and two end faces each of which contacts one of said plane facesof said outer portion, said sleeve having an axial length slightly greater than the axial distance between said plane faces so that said sleeve is resiliently compressed in axial direction whereby an axial force is created which produces friction between said end faces of said sleeve and said plane faces requiring a certain force for relative turning movement between said sleeve and said plane faces; and pressing means comprising a metal ring surrounding at least the central tu: bular portion of said sleeve, said metal ring having the shape of a cylindrical crown and having its lower and upper inner edges bevelled and having between said bevelled edges an inner annular pressing surface contacting the outer anular surface of said central tubular portion, the diameter of said inner pressing surface being smaller than the diameter of said outer surface of said central tubular portion so that said central tubular portion is radially compressed and exerts on said inner portion an inwardly directed radial pressure which produces friction between said inner surface of said sleeve and said outer surface of said inner portion requiring for relative turning movement between said sleeve and said inner portion a greater force than said first mentioned certain force so that said sleeve and said inner portion do not turn relative to each other and so that said end faces of said sleeve slide on said plane faces when one of said units is rotated with respect to the other unit and only said plane faces will be subjected to wear by friction produced by said sleeve, while axial displacement of one of 'said units results in axial sliding of said sleeve on said inner portion. 7

2. In combination, an inner portion of a first unit and an outer portion of a second unit, said inner portion having an axis and said outer portion surrounding said inner portion and extending'coaxially thereto, one of said units being arranged for rotary motions about said axis with respect to the other unit, said outer portion having an annular cavity facing said inner portion, said annular cavity being delimited in axial direction by two plane faces substantially perpendicular to said axis; a rubbery tance between said plane faces so that saidsleeve is re siliently compressed in axial direction whereby an axial force is created which produces friction between said end faces-of said sleeve and said planefaces requiring a certain force for relative turning movement between said sleeve and said plane faces, said rubbery sleeve having a central portion and being provided with a peripheral groove in the central portion of its cylindrical outer face; and pressing means comprising a metal ring surrounding at least the central tubular portion of said sleeve, said metal ring having a trapezoidal shape in cross section with a small central cylindrical face and two inclined faces adjacent said cylindrical face, said metal ring engaging said groove by means of its small inner face and said inclined faces and said small inner face having a diameter which is smaller than the smallest diameter of said groove in said central tubular portion so that said central tubular portion is radially compressed and exerts on said inner portion an inwardly directed radial pressure which produces friction between said inner surface of said sleeve and said outer surface of said inner portion requiring for relative turning movement between said sleeve andsaid inner portion a greater force than said first mentioned certain force so that said sleeve and said inner portion do not turn relative to each other and so that said end faces of said sleeve slide on said plane faces when one of said units is rotated with respect to the other unit and only said plane faces will be subjected to wear by friction produced by said sleeve, while axial displacement of one of said units results in axial sliding of said sleeve on said inner portion.

3. In combination: an inner portion of a first unit and an outer portion of a second unit, said inner portion having an axis and said outer portion surrounding said inner portion and extending coaxially thereto, one of said units being arranged for rotary motions about said axis with respect to the other unit, said outer portion having an annular cavity facing said inner portion, said annular cavity being delimited in axial direction by two plane faces substantially perpendicular to said axis; a rubbery sleeve located in said cavity between said two plane faces and surrounding said inner portion, said sleeve having an inner surface contacting the outer surface of said inner portion, and two end faces each of which contacts one of said plane faces of said outer portion, said sleeve having an axial length slightly greater than the axial distance between said plane faces so that said sleeve is resiliently compressed in axial direction whereby an axial force is created which produces friction between said end faces of said sleeve and said plane faces requiring a certain force for relative turning movement between said sleeve and said plane faces, said rubbery sleeve having a central portion and being provided with a peripheral groove in the central portion of its cylindrical outer face; and pressing means comprising a metal ring surrounding at least the central tubular portion of said sleeve, said metal ring having a circular shape in cross section, said metal ring engaging said groove and having a minimum diameter which is smaller than the minimum diameter of said groove in said central'tubular portion so that said central tubular portion is radially compressed and exerts on said inner portion an inwardly directed radial pressure which produces friction between said inner surface of said sleeve and said outer surface of said inner portion requiring for relative turning movement between said sleeve and said inner portion a greater force than said first mentioned certain force so that said sleeve and said inner portion do not turn relative to each other and so that said end faces of said sleeve slide on said plane faces when one of said units is rotated with respect to the other unit and only said plane faces will be subjected to wear by friction produced by said sleeve, while axial displacement of one ofsaid units results in axial sliding of said sleeve on said inner portion.

4. In combination: an inner portion of a first unit and an outer portion of a second unit, said inner portion having an axis and said outer portion surrounding said inner portion and extending coaxially thereto, one of said units being arranged for rotary motions about said axis with respect to the other unit, said outer portion having an annular cavity facing said inner portion, said annular cavity being delimited in axial direction by two plane faces substantially perpendicular to said axis, said inner portion being cylindrical and provided with a net of infinitesimal oblique grooves and ribs; :1 rubbery sleeve located in said cavity between said two plane faces and surrounding said inner portion, said sleeve having an inner surface contacting the outer surface of said inner portion, and two end faces each of which contacts one of said plane faces of said outer portion, said sleeve having an axial length slightly greater than the axial distancebetween said plane faces so that said sleeve is resiliently compressed in axial direction whereby an axial force is created which produces friction between said end faces of said sleeve and said plane faces requiring a certain force for relative turning movement between said sleeve and said plane faces; and pressing means comprising a metal ring surrounding at least the central tubular portion of said sleeve, said metal ring having an inner annular pressing surface contacting the outer annular surface of said central tubular portion only, the diameter of said inner pressing surface being smaller than the diameter of said outer surface of said central tubular portion so that only said central tubular portion is radially compressed and exerts on said inner portion an inwardly directed radial pressure which produces friction between said inner surface of said sleeve and said outer surface of said inner portion requiring for relative turning movement between said sleeve and said inner portion a greater force than said first mentioned certain force so that said sleeve and said inner portion do not turn relative to each other and so that said end faces of said sleeve slide on said plane faces when one of said units is rotated with respect to the other unit and only said plane faces will be subjected to wear by friction produced by said sleeve, while axialdisplacement of one of said units results in axial sliding of said sleeve on said inner portion.

5. In combination: an inner portion of a first unit and an outer portion of a second unit, said inner portion having an axis and said outer portion surrounding said inner portion and extending coaxially thereto, one of said units being arranged for rotary motions about said axis with respect to the other unit, said outer portion having an annular cavity facing said inner portion, said annular cavity being delimited in axial direction by two plane faces substantially perpendicular to said axis, said inner portion having fiat faces and rounded edges separating said flat faces; a rubbery sleeve located in said cavity between said two plane faces and surrounding said inner portion, said sleeve having an inner surface contacting the outer surface of said inner portion, and two end faces each of which contacts one of said plane faces of said outer portion, said sleeve having an axial length slightly greater than the axial distance between said plane faces so that said sleeve is resiliently compressed in axial direction whereby an axial force is created which produces friction between said end faces of said sleeve and said plane faces requiring a certain force for relative turning movement between said sleeve and said plane faces; and pressing means comprising a metal ring surrounding at least the central tubular portion of said sleeve, said metal ring having an inner annular pressing surface contacting the outer annular surface of said central tubular portion only, the diameter of said inner pressing surface being smaller than the diameter of said outer surface of said central tubular portion so that only said central tubular portion is radially compressed and exerts on said inner portion an inwardly directed radial pressure which produces friction between said inner surface of said sleeve and said outer surface of said inner portion requiring for relative turning movement between said sleeve and said inner portion a greater force than said first mentioned certain force so that said sleeve and said inner portion do not turn relative to each other and so that said end faces of said sleeve slide on said plane faces when one of said units is rotated with respect to the other unit and only said plane faces'will be subjected to wear by friction produced by said sleeve, while axial displacement of one of said units results in axial sliding of said sleeve on said inner portion.

References Cited in the file of this patent UNITED STATES PATENTS Feurer Aug. 13, 1946 Soguel Ian. 29, 1957 Piquerez Sept. 17, 1957 FOREIGN PATENTS 7 Switzerland Aug. 1, 1941 Switzerland Nov. .17, 1941 Switzerland June 16, 1942 Switzerland n Aug. 2, 1943 Switzerland Oct. 2, 1944 Switzerland Oct. 2, 1944 Switzerland Mar. 16,1946 Switzerland Sept. 16, 1948 Switzerland Oct. 16, 1948 Switzerland Jan. 3, 1955 

1. IN COMBINATION; AN INNER PORTION OF A FIRST UNIT AND AN OUTER PORTION OF A SECOND UNIT, SAID INNER PORTION HAVING AN AXIS AND SAID OUTER PORTION SURROUNDING SAID INNER PORTION AND EXTENDING COAXIALLY THERETO, ONE OF SAID UNITS BEING ARRANGED FOR ROTARY MOTIONS ABOUT SAID AXIS WITH RESPECT TO THE OTHER UNIT, SAID OUTER PORTION HAVING AN ANNULAR CAVITY FACING SAID INNER PORTION, SAID ANNULAR CAVITY BEING DELIMITED IN AXIAL DIRECTION BY TWO PLANE FACES SUBSTANTIALLY PERPENDICULAR TO SAID AXIS; A RUBBERY SLEEVE LOCATED IN SAID CAVITY BETWEEN SAID TWO PLANE FACES AND SURROUNDING SAID INNER PORTION, SAID SLEEVE HAVING AN INNER SURFACE CONTACTING THE OUTER SURFACE OF SAID INNER PORTION, AND TWO END FACES EACH OF WHICH CONTACTS ONE OF SAID PLANE FACES OF SAID OUTER PORTION, SAID SLEEVE HAVING AN AXIAL LENGTH SLIGHTLY GREATER THAN THE AXIAL DISTANCE BETWEEN SAID PLANE FACES SO THAT SAID SLEEVE IS RESILIENTLY COMPRESSED IN AXIAL DIRECTION WHEREBY AN AXIAL FORCE IS CREATED WHICH PRODUCES FRICTION BETWEEN SAID END FACES OF SAID SLEEVE AND SAID PLANE FACES REQUIRING A CERTAIN FORCE FOR RELATIVE TURNING MOVEMENT BETWEEN SAID SLEEVE AND SAID PLANE FACES; AND PRESSING MEANS COMPRISING A METAL RING SURROUNDING AT LEAST THE CENTRAL TUBULAR PORTION OF SAID SLEEVE, SAID METAL RING HAVING THE SHAPE OF A CYLINDRICAL CROWN AND HAVING ITS LOWER AND UPPER INNER EDGES BEVELLED AND HAVING BETWEEN SAID BEVELLED EDGES AN INNER ANNULAR PRESSING SURFACE CONTACTING THE OUTER ANUAL SURFACE OF SAID CENTRAL TUBULAR PORTION, THE DIAMETER OF EACH INNER PRESSING SURFACE BEING SMALLER THAN THE DIAMETER OF SAID OUTER SURFACE OF SAID CENTRAL TUBULAR PORTION SO THAT SAID CENTRAL TUBULAR PORTION IS RADIALLY COMPRESSED AND EXERTS ON SAID INNER PORTION AN INWARDLY DIRECTION RADIAL PRESSURE WHICH PRODUCES FRICTION BETWEEN SAID INNER SURFACE OF SAID SLEEVE AND SAID OUTER SURFACE OF SAID INNER PORTION REQUIRING FOR RELATIVE TURNING MOVEMENT BETWEEN SAID SLEEVE AND SAID INNER PORTION A GREATER FORCE THAN SAID FIRST MENTIONED CERTAIN FORCE SO THAT SAID SLEEVE AND SAID INNER PORTION DO NOT TURN RELATIVE TO EACH OTHER AND SO THAT SAID END FACES OF SAID SLEEVE SLIDE ON SAID PLANE FACES WHEN ON OF SAID UNITS IS ROTATED WITH RESPECT TO THE OTHER UNIT AND ONLY SAID PLANE FACES WILL BE SUBJECTED TO WEAR BY FRICTION PRODUCED BY SAID SLEEVE, WHILE AXIAL DISPLACEMENT OF ONE OF SAID UNITS RESULTS IN AXIAL SLIDING OF SAID SLEEVE ON SAID INNER PORTION. 